Flying and biting insects are presently controlled by the application of insecticides directed either at immature stages (larvicides) or adults (adulticides). These compounds are generally applied as a broadcast spray from either the air or the ground. This broadcast application generally results in two levels of failure. First, large areas of land and water are treated where there are no insects. Second, non-target, beneficial organisms are oftentimes affected and sometimes killed by the broadcast treatment.
Solid CO.sub.2 (dry ice) has been used as an attractant for flying and biting insects insects to gather data about this insect population density. This data has been used to aid in determining when broadcast application of insecticides is needed, and in what amounts. While dry ice has been effective as bait for insects because it sublimates CO.sub.2 gas into the atmosphere, there have been no effective methods of metering the amounts of CO.sub.2 gas released from a source of CO.sub.2 for attracting insects.